The denunciations of Edward Snowden have been accompanied by an unconvincing refrain—that there was a way for him to force a debate on the U.S. surveillance programs that troubled him without exposing America’s espionage capabilities to the world. Snowden’s leaks raised “legitimate policy questions,” President Obama said in a recent interview with the New Yorker magazine. But “the benefit of the debate he generated was not worth the damage done, because there was another way.”

It’s hard to see this supposed alternate path. Was Snowden supposed to raise his misgivings—now shared by many Americans—with spy agency officials who built the programs? Appeal to the secret court that approved them? Or turn to congressional oversight committees that have responded to his revelations by fighting to keep the surveillance operations intact?

The course that Snowden chose instead—surreptitiously stockpiling thousands of classified files, leaking them to news organizations and finally fleeing first to Hong Kong and then Russia—has been polarizing. He has been condemned as treasonous and hailed as courageous. Either way, his story is one of the most compelling in the history of American espionage.

“The Snowden Files” by Luke Harding, a correspondent for The Guardian newspaper, which broke the initial Snowden story, is the first to assemble the sequence of events in a single volume. The book captures the drama of Snowden’s operation in often cinematic detail but doesn’t necessarily enhance our understanding of the magnitude and impact of the leaks. It is most successful when focused tightly on its then-29-year-old protagonist, whose youth and low station in the spy world were so at odds with the caliber of the material he accessed that his journalist contacts, upon meeting him for the first time, shook their heads in disbelief. Snowden comes across as almost icily composed. He seems to have been undaunted by the challenge of outmaneuvering his employer, the National Security Agency, the largest spy agency in the world. He choreographed his encounters with journalists and revealed himself to the world largely on his own terms.

How he acquired this equanimity is less clear, and insights into his upbringing and emotional makeup are elusive. Searching for clues, Harding pores over hundreds of anonymous Snowden postings on a technology website from the time he was 19, and finds a tangle of contradictions. Among them is a profanity-laced tirade against leaks. Outraged by classified details that surfaced in a 2009 New York Times story, Snowden called the paper “worse than Wikileaks” and said its anonymous sources “should be shot.”

By then, Snowden had already spent several years working as a computer specialist for the CIA, a position he secured based on technology skills impressive enough to offset gaping holes in his resume, including the lack of a high school diploma. After a stint working at a CIA station in Switzerland, he quit the agency but kept his security clearance—a ticket to more lucrative contracting assignments for the National Security Agency, the U.S. eavesdropping behemoth based not far from the Maryland suburbs where Snowden grew up.

Snowden’s online postings evaporated at this point, leaving no trace of his apparent evolution on the issue of leaks or his emerging dismay with the vast NSA surveillance programs that his status as a “sysadmin” enabled him to explore. Among them was an operation that secretly amassed the phone records—numbers dialed and duration but not content of calls—of nearly every U.S. citizen. For Snowden, who Harding writes was so adapted to life online that his skin took on the pallor of the vampire played by Robert Pattinson in the “Twilight” films, the intrusions were a threat to his entire ecosystem.

In December 2012, Snowden took his first tentative step toward exposing the NSA’s pervasive reach, sending a cryptic email to Guardian columnist Glenn Greenwald saying, “I have some stuff you might be interested in.”

Although the book is billed as “the inside story of the world’s most wanted man,” there is no indication Harding had direct contact with his subject. Instead, it reads more like the inside account of Snowden’s interactions with The Guardian. The details drawn from those encounters are fascinating, if not always illuminating. Snowden was so concerned about security at the hotel where they met that the few times he left his room he placed a glass of water behind the door, positioned to spill on a piece of tissue paper marked with a symbol sketched in soy sauce.

Harding describes Snowden’s elation when The Guardian’s first story broke online, the avalanche of articles that followed, and the remarkable scene when British authorities showed up at The Guardian’s offices to supervise the destruction of the devices containing Snowden’s files.

As Snowden leaves Hong Kong for Russia, the thrust of the narrative leaves with him. Harding, a former correspondent in Moscow, captures the irony and uncertainty of Snowden’s new situation. “The hacker turned whistle-blower had got his asylum,” Harding writes. But in reality “he was, in some informal way, [Russia’s] prisoner.”

Harding doesn’t address deeper questions about Snowden, including whether the “damage” cited by Obama might have been less if Snowden had limited the contents of his trove to the programs he found most troubling. Nor does he examine whether news organizations should have exercised more restraint with those documents. Harding summarizes the cascading revelations as The Guardian picked through that material. But it is from a British perspective that overlooks some significant U.S. developments, and underplays important work done by other journalists, including Barton Gellman of The Washington Post.

“The Snowden Files” won’t be the last book on this subject nor likely the best, with Gellman and Greenwald titles already in the works. But Harding has delivered a clearly written and captivating account of the Snowden leaks and their aftermath, succeeding beyond its most basic ambition, which was to arrive in bookstores first.

Greg Miller is national security correspondent for The Washington Post.